Animal Rescue: Medicine

Find the sleeping Skag, known as Dukino at the end of the Lynchwood train tracks to get the mission.

Shoot or smash the chain (glowing green) that keeps Dukino confined

Note: There is a bug that makes it so you cannot destroy the chain. Simply re-loading the game will usually fix this problem.

Follow your map marker to get "puppy medicine." Dukino will not follow -- just leave him behind. The medicine is on a roof top. Take the stairs of the building next door, jump across and grab the medicine.

Bring the medicine to Dukino and place it on the marked ground.

Next, Dukino needs food. You have to head to the upper town area known as Gunslinger's Corner and follow the five markers on your map. There will be blood.

Head back to Dukino and drop the food in the chute attached to Dukino's hut. Dukino will "eat" -- when he comes out, he'll be much bigger. Turn in the mission to move on to Animal Rescue: Food